Temperature rises when not in motion. Temperature according to the gauge star ts to rise when in traffic or at a Traffic light. Temperature spikes all the way to the red on the gauge. Once in motion temperature settles back at around the 190s. No fluid leaking, overflow reservoir at correct levels. Installed a new thermostat yesterday and it has had no affect .

 

Check the engine cooling fan. Should come on at about 217 degrees. Will be on anytime the AC or defrost is used.
Fwiw. Posting the model, engine and mileage would help.

What was the actual temp reading if it reached into the "red" ? Anything above 250 degrees could have caused serious damage.

 

Sounds like a bad fan to me.

 

Welcome to the site, I see you have a 2011, and you replaced the thermostat, with an AC Delco 131-158, 180 degrees F .
Or did you use s different brand , is it a 180 F thermostat?
After you replaced the thermostat did you burp the coolant ?

https://www.chevyhhr.net/forums/how-...-system-60614/

 

Or something blocking the radiator.
Also if there is no flow from a bad water pump impeller.

 

Sorry...2011 2.2 liter. Checked all items and all were working. After engine cooled I removed the radiator cap and burped the system and added coolant. I changed the t-stat last week. I got a lot of air out of the system today. Drove around town for 30 min. and the temp never went past normal.

 

Just gas, good burp, baby!